1. Field of the Invention
The invention relates to gas turbine engine rotors and vane assemblies and, particularly, to composite rotors and stators with integral airfoils for aircraft gas turbine engines.
2. Description of Related Art
Integrally bladed rotors (IBRs) or bladed disks often called (BLISKS) are known in the art for use in gas turbine engines. Turbofan gas turbine engines generally includes a forward fan and booster compressor, a middle core engine, and an aft low pressure power turbine. Blisks have been manufactured of metallic materials usually as single items machined from a solid metal billet or as several elements welded together. Metal BLISKS are relatively heavy. Metals have a lower specific strength and have very little inherent damping as compared to composite materials.
Composite integrally bladed rotors for use in gas turbine engines have been disclosed in several patents such as U.S. Pat. Nos. 4,747,900, 4,786,347, and 7,491,032. Composite integrally bladed rotors are subject to large forces which must be taken into account in designing the construction of the rotor to preserve its integrity. In the rotor disc, the major forces are exerted in circumferential directions so an ability to absorb hoop stress is important, whereas in the aerofoil blades radially exerted forces predominate. Composite material used in such rotors typically include a resin (such as epoxy) which has low inherent strength. The composite material has a specific strength higher than that of metal due to the inclusion of fibers normally of the same material embedded in a matrix of the composite material. The fibers are known to be strongest in tension so the direction of the forces in the finished component will, at least in part, determine its strength. In some instances, the structural design of the component has been influenced by the need for fiber orientation.
Composite matrix integrally bladed rotors, disks, vanes, and the methods for manufacturing them are very labor intensive, time-consuming, and very expensive. It is highly desirable to have a design and method for manufacturing composite matrix integrally bladed rotors, disks, and vanes that is far less labor intensive, time-consuming, and expensive. It is highly desirable to have a design and method for manufacturing composite matrix integrally bladed rotors, disks, and vanes that are strong, allows for a central bore and yet is relatively quick and easy to manufacture.